In Patent Literature 1, there is disclosed a wireless audio system, which includes a plurality of wireless speakers grouped into a plurality of groups, and is capable of playing back music data that is different for each group. In the wireless audio system, for each group, the plurality of wireless speakers belonging to the group perform arbitration to select one wireless speaker from among those wireless speakers. Then, the selected wireless speaker serves as a group leader to receive from a user an operation for the plurality of wireless speakers belonging to the same group and transmit a control signal to those wireless speakers. With this wireless audio system, for example, when a plurality of wireless speakers are installed in each of a plurality of rooms, and the wireless speakers installed in the same room are set as belonging to the same group, music data that is different for each room may be played back.
Further, in Patent Literature 2, there is disclosed a wireless communication system capable of acquiring accurate positional information and enabling construction of a communication system that suppresses costs. This wireless communication system measures a distance to a wireless device based on a received radio wave strength of a wireless signal output from the wireless device.